Recovery of fatty acids



l ateni:ed Got. 23, a I Q n I I Q RECOVERY OF FATTY ACIDS Hans Franzen, Mannheim, and Guenther Kunze, Oppau, Germany No Drawing. Application May 6, 1931, Serial No. 535,574. In Germany May 16, 1930 7 Claims. (Cl. 202-52) The present invention relates to the recovery-ting of large molecules into smaller ones, and the of fatty acids from the products of the 'destruclike, such as occur in other'distillation processes tive oxidation hydrocarbons. and which for many purposes, as for example by We have found that the crude mixture of alireason of the deterioration in the odour, are unphatic carboxylic acids obtainable from the desirable, do not take place. The fatty acids 30 products of a destructive oxidation with gaseous obtained are especially pale by reason of the oxidizing agents, such as oxygen or air, of difprotective course of the distillation. They have ficultly volatile, non-aromatic hydrocarbons, only a slight odour, because by the action of the such as petroleum, fractions-thereof, as for. exsmall drops of liquid a particularly efilcient de- 10 ample middle oils, solid or liquid paraffin wax odorizing takes place. 5 or oil fractions containing the same, and like For carrying out the process it is preferable to hydrocarbon mixtures, can be freed in a very use a continuously operating apparatus, such as advantageous manner from hydroxy carboxylic is described in the U. S. Patent No. 1,766,863. acick and their derivatives by treating the crude The injected liquid is either introduced through mixture at elevated temperatures, such as besuitable nozzles, as for example according to the 70 tween about 150 and about 300 C. under reduced U. S. application, Ser. No. 334,183, filed by one pressure, as for example from 10 to 50 millimeof the present inventorson January 22, 1929, or tres mercury gauge with a spray of finely diwhile employing neutral gases or vapours, such vided liquids, preferably boiling below 105 C. at as carbon dioxide, nitrogen or superheated steam,

atmospheric pressure, such as water, benzine, as carrier substances. Wet steam, which is a 7 benzene, trichlorethylene, ethyl alcohol and like suspension of small drops of water in saturated organic liquids inert to the initial materials, for steam, is especially suitable. Generally speaking example in the form of dust or mist and, if deit is advantageous to regulate a definite optimum sired with an inert gaseous carrier. In this manratio between the amounts of distillate and inher a practically quantitative separation takes jected liquid, the said ratio being dependent on 80 place between the fatty acids from hydroxycarthe nature of the product to be distilled and on boxylic acids, estolides (inner esters of hydroxythe dimensions of the apparatus; When em- ,carboxylic acids containing the group ploying water, as for example with an apparatus according to the said Patent No. 1,766,863 having 0-0(3*OH"GH(OH)"'OOOH an hourly efficiency of 10 kilograms of distillate CH1CH with an average molecular weight of the fatty \CHLHCOOH acids of 250', the optimum amount of injected water is 12 kilograms and 140 kilograms with an a d ot e byproducts of the Oxidation Still p apparatus having an hourly efliciency of 400 kilo- 35 ent in the mixture. and this is f imp r nce grams of distillate. The most favourable ratio 90 becaus the hy roxy ar xylic acids and their of distillate to injected liquid is readily deterderivatives unfavourably influence the value of i d by experiment for each particular initial he mixtures, 85 for example their pacity for material and apparatus. When working below b in sal d out i the preparation of p the optimum, the efliciency of the apparatus 4 their colour and their smell. Contrasted with usually falls and the distillate usually has a 95 other distilling processes, such as ordinary vacmarked odour and contains hydroxycarboxylic uum distillation or distillation with superheated acids. If too much injected liquid be employed, st am, di lla nracticellyifree m dr xythe colour of the distillate may be impaired by Carb y c a s are Obtained T y fl particles of crude product carried over.

boxylic acids and their derivatives remain in the When working continuously, as for example 1 distillation residue, and the distillates do not according to the said Patent No. 1,766,863, a'suflicontain any decomposition products f h hycient throughput speed must be ensured by withdroxycarboxylic acids and their derivatives. drawing a quantity of residue corresponding to The treatmentof the oxidation products in about 5 to 10 per cent of the crude initial mateaccordance with the present invention is so prorial from the last reaction chamber. Thus the 5 tective that chemical processes, such as splitting yield can only amount to the maximum of off water from the hydroxycarboxylic acidswith to per cent even if products which are comthe formation of unsaturated acids, formation of pletely volatile at the distillation temperature are unsaponifiable substances, such as hydrocarbons subjected to distillation. Yields of per cent 5 or alcohols, by splitting off carbon dioxide, splitof the theoretical yield may be obtained for such 1m products, however, by adding to the material to be distilled before its entry into the distilling apparatus, substances which are liquid but not volatile at theworking temperature. Suitable substances for this purpose are for example hydrocarbons of high boiling point, such as paramn oil or soft paraflln wax, residues from a previous distillation and the like, for example in an amount of from 10 to 20 per cent of the initial material to be distilled. These additions,

which may be repeatedly employed without injury, act as carrier liquids and render it possible to distill the fatty acids quantitatively from the crude material. This is especially advantageous in redistillations, in which otherwise a part of the distillation material remains as a residue, the yields not only being impaired but the properties of the distillate altered by difilcultly volatile constituents remaining behind.

The following examples will further'illustrate the nature of this invention, but the invention is not restricted to these examples.

Example 1 products with basic agents and, if desired, from subsequent mechanical separation, of the greater part of the unsaponiflable materials present, separating a part of the soap solution, decomposing any emulsion of the remaining soap solution with the said extraction agent by adding small quantities of low molecular aliphatic alcohols and separating the layers formed, the soap solution being then worked into free acids, is treated continuously with saturated steam, laden with water mist of 55 C., at 280 .C. and at a pressure of 28 millimeters mercury'gauge. An almost odourless fatty acid mixture having a pale yellowish white colour and a content of 0.1 per cent of hydroncarboxylic acids is obtained as the distillate in a yield of 92 per cent of the initial mixture of acids.

Example 2 Example 3 A crude mixture of acids from the so-called distillate oil of a paraiiin wax oxidation (that is the low molecular constituents distilling over during theoxidation with the aid of air at about 140 to 160 C.) having a mean molecular weight of 160 and containing 2.6 per cent of hydroxycarboxylic acids ar treated at from 240 to 250 C. and 18 millimetres mercury gauge with saturated steam laden with water mist of a temperature of 57C. A pale yellow liquid consisting of fatty acids and free from hydroxycarboxylic acids is obtained in a yield of 95 per cent with reference to the initial acid mixture employed.

Example 4 Distillation fatty acids obtained by a direct distillation by heating of the acids from the oxidation of hard paraflin wax with the aid of air and conta 1 per cent of hydroxycarboxylic acids are well e with 20 per cent their weight of distillation residu obtained in the process described in Example 1 and treated continuously according to Example 1. Fatty acids free from hydroxycarboxylic acids and greatly improved in odour and colour are obtained in a yield of 99 per cent with reference to the initial acid mixture employed.

What we claim is:

1. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of dimcultly volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products a finely divided liquid inert thereto, at a pressure below atmospheric pressure and at a temperature above the boiling point of said liquid at the pressure employed, explo'sively converting said liquid into a vapor which substantially, selectively, distills off the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate. i

2. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of difficultly volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hy-' droiw-carboxylic acids, which comprises introducing into said products a mixture of a finely divided liquid inert thereto and an inert gaseous v carrier, at a pressure below atmospheric pressure and at a temperature above the boiling point of said liquid at the pressure employed, explosively converting said liquid into a vapor which substantially, selectively, distills off the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

3. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of, difflcultiy volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products a finely divided liquid, boiling below 105 C. at atmospheric pressure and inert to said products, at a pressure below atmospheric pressure and at a temperature above the boiling point of said liquid at the pressure employed, explosively converting said liquid into a vapor which substantially, selectively, distills off the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

4. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of difflcultly volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hydroxy-carboiwlic acids, which comprises introducing into said products finely divided water, at a pressure below atmospheric pressure and at a temperature above the boiling point of waterat the pressure employed, explosively converting said water into steam which substantially, selectively; distills off the fatty -acids from said products without a conversion of said hydroxycarboxylic acids, and collecting the distillate,

5. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of difficultly volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products a mixture of finely divided water and an inert gaseous carrier, at a pressure below atmospheric pressure and at a temperature above the boiling point of water at the pressure employed, explosively converting said water into steam which substantially,

selectively, distills off the fatty acids from said products without a conversion of said hydroxycarboxylic acids, and collecting the distillate.

6. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of paraflin wax, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products wet steam, at a pressure below atmospheric pressure and at a temperature above the boiling point of water, explosively converting the wet steam into dry steam which substantially, selectively, distills of! the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

, 7. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of paraflin wax, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products wet steam at a pressure between 10 and 50 millimetres mer-. cury gauge at between 150 and 300 C., explosively converting the wet steam into dry steam which substantially, selectively, distills oil the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

HANS FRANZEN GUENTHER KUNZE.

mu s; or CORRECTION.

Patent No. l, 977, 988.

October 23. 1934.

HANS FRANZEN, ET AL.

It is hereby certified that the above numbered patent was erroneously issued to the inventors whereas said patent should have been issued to I. G. Farbenindustrie Aktiengesellscbaft, Frankfort-on-the-Main, Germany, as assignee of the entire interest in said invention, as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction therein that the same may'conform to therecord of the case in the Patent Office.

Signed and sealed this 12th day of February, A. D. 1935.

(Seal) 7 Leslie Frazer Acting Commissioner of Patent a temperature above the boiling point of waterat the pressure employed, explosively converting said water into steam which substantially, selectively; distills off the fatty -acids from said products without a conversion of said hydroxycarboxylic acids, and collecting the distillate,

5. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of difficultly volatile, non-aromatic hydrocarbons, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products a mixture of finely divided water and an inert gaseous carrier, at a pressure below atmospheric pressure and at a temperature above the boiling point of water at the pressure employed, explosively converting said water into steam which substantially,

selectively, distills off the fatty acids from said products without a conversion of said hydroxycarboxylic acids, and collecting the distillate.

6. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of paraflin wax, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products wet steam, at a pressure below atmospheric pressure and at a temperature above the boiling point of water, explosively converting the wet steam into dry steam which substantially, selectively, distills of! the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

, 7. The process for the recovery of pure fatty acids from the acid products of the destructive oxidation, with gaseous oxidizing agents, of paraflin wax, said products containing a substantial amount of hydroxy-carboxylic acids, which comprises introducing into said products wet steam at a pressure between 10 and 50 millimetres mer-. cury gauge at between 150 and 300 C., explosively converting the wet steam into dry steam which substantially, selectively, distills oil the fatty acids from said products without a conversion of said hydroxy-carboxylic acids, and collecting the distillate.

HANS FRANZEN GUENTHER KUNZE.

mu s; or CORRECTION.

Patent No. l, 977, 988.

October 23. 1934.

HANS FRANZEN, ET AL.

It is hereby certified that the above numbered patent was erroneously issued to the inventors whereas said patent should have been issued to I. G. Farbenindustrie Aktiengesellscbaft, Frankfort-on-the-Main, Germany, as assignee of the entire interest in said invention, as shown by the records of assignments in this office; and that the said Letters Patent should be read with this correction therein that the same may'conform to therecord of the case in the Patent Office.

Signed and sealed this 12th day of February, A. D. 1935.

(Seal) 7 Leslie Frazer Acting Commissioner of Patent 

